syms x s t v
D1= sqrt(t); 
L1 = laplace(D1) 
D2 = 1/sqrt(s); 
L2 = laplace(D2) 
D3 = exp(-a*t); 
L3 = laplace(D3,x) 
D4 = 1 - cos(t*v); 
L4 = laplace(D4,v,x)
